1) Field of the Invention
This invention relates generally to fabrication of semiconductor devices and more particularly to performing a pre-amorphization implant (PAI) during a salicide process.
2) Description of the Prior Art
Self-aligned silicide (salicide) formation is widely used in semiconductor manufacting. It is well known that salicide formation is enhanced by doping the silicon region on which salicide formation will occur. This doping process is known as pre-amorphization implant (PAI). PAI is widely, used in 0.25 .mu.m devices. However, if the salicide process parameters are not precisely controlled, voids can form in the resist protect oxide (RPO) resulting in juction leakage. As PAI energy increases and/or pre-metal dip time increases RPO voids increase.
The importance of overcoming the various deficiencies noted above is evidenced by the extensive technological development directed to the subject, as documented by the relevant patent and technical literature. The closest and apparently more relevant technical developments in the patent literature can be gleaned by considering the following patents.
U.S. Pat. No. 4,635,347 (Lein et al.) shows a self-aligned TiSi.sub.x gate and contact forming process.
U.S. Pat. No. 5,605,854 (Yoo) shows a TiSi.sub.x process.
U.S. Pat. No. 5,656,546 (Chen et al.) shows a self-aligned TiN/TiSi.sub.x process.